Various prosthetic repair materials have been proposed for mending inguinal hernias and for reconstructing the abdominal and chest wall. MARLEX mesh, a single bar warp knit, dual course Atlas polypropylene monofilament fabric, is exemplary of an implant material that has been successfully used in soft tissue reinforcement and defect closure.
A concern had been raised that MARLEX mesh may form postoperative adhesions with the abdominal viscera, such as the intestines, when used in the repair of inguinal hernias and other abdominal wall defects. Similarly, there was a suggestion that intra-thoracic viscera (i.e. heart and lungs) could adhere to the porous prosthetic repair material after chest wall reconstruction. To alleviate these concerns, it had been proposed in U.S. Pat. No. 5,593,441, assigned to C. R. Bard, Inc., also the assignee of the present application, to cover the MARLEX fabric (or other tissue infiltratable material) with an adhesion resistant barrier, such as a sheet of expanded PTFE. The composite prosthesis is surgically placed so that the barrier isolates the sensitive viscera from the porous fabric, preventing the formation of postoperative adhesions.
One method of forming the composite is to laminate the mesh and adhesion resistant cover together. Preliminary investigation, however, suggests that fusing a sheet of MARLEX to a barrier layer of ePTFE may detrimentally affect the tissue infiltratability of the prosthesis. With one surface of the porous fabric covered by the ePTFE, the ingrowing tissue may be unable to completely incorporate the mesh.
Accordingly, there is a need for an improved laminate prosthesis for the repair of tissue or muscle wall defects that exhibits acceptable tissue ingrowth properties.